Area Lamp - Part 5

Posted 01.06.2019 by Mario & Kitty Costello

After the base was finished curing, the sections of the mold form were dis-assembled and removed. Everything looks  fine. The metal spine that was placed in the back of the base took some convincing, but we had thought ahead and put  threaded holes into the piece of aluminum that created that space, so all we had to do was slowly thread the screws  into the holes and it pushed the part out of the molded form.

Sander image

The base had a matte finish to it and now began the process of refining the form- we used a 5” angle grinder with  sanding discs that have diamonds of various grits embedded into them and a dust shroud that hooks up to a vacuum  cleaner to keep the dust down. The coarse grits allowed us to change further smooth the corners and increase the radius  a bit while the finer grits brought the surface to a polish (video_1.mov). This was all done dry, but can be done with  water to aid the process. The finer grits started to “smear” and turn the surface black during the process (probably  from the binder on the sanding discs getting too hot), so we cleaned off the unwanted coloring and finished it by hand  with some sponges that have a fine diamond coating on them. This process was done with water from a spray  bottle to help lubricate things.

Tube image

The large arc of the “spine” section came back from the metal fab shop that did the tube rolling for us and was right on target in terms of dimensions. The ends were slightly dis-figured from the rolling process, so a little had to be  trimmed off. To strengthen the connection between the straight tube and the arc tube, we inserted a piece of 1018 steel tubing inside the brass tube- luckily the outer diameter of the round tube fit almost perfectly inside the square tube.  And it allows the whole arc section to swing back and forth and adds some stiffness to the structure.  Finally seeing the actual part leaning against the side of the shop, we were starting to worry about whether the whole  thing was going to tip over or not. It was big. And heavy.

Connector image

Here’s a detail of the connector that holds the glass globe- you can see that it allows everything to pivot in another axis. Here’s a detail of the whole assembly that holds the frosted glass globe in place along with the bulb and socket- we used one of our coaster bodies as the cap for this assembly!

Bulb image

The white balls are made  from Delrin, another slippery plastic, and are meant to hold things “softly” with a bit of compliance so the globe  doesn’t crack when secured.

Lamp base image

And another detail shot showing how the brass tube fits into the recess that was part of the molding process .

The finished lamp now sits in our living room and works great! And we only bump our heads into it occasionally.

Finished lamp image
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Please allow 5 days for fabrication.